Nicotinamide riboside (NR)

What it is

Nicotinamide riboside (NR) is a naturally occurring form of vitamin B3 found in tiny amounts in milk and some foods. Supplements use a manufactured version.

It is taken as a precursor to NAD+, a molecule involved in energy metabolism that tends to decline with age. It is one of the more researched NAD+ boosters, with a number of human trials.

It is sold in the UK as a food supplement and is closely related to NMN.

How it works

NR is converted into NMN and then into NAD+ inside cells. Raising NAD+ is thought to support mitochondria and enzymes involved in cell repair, though whether that matters in healthy people is not proven.

What the evidence says

• Strong Raising blood NAD+ levels
  Multiple human trials show oral NR increases NAD+ and related metabolites.
• Limited Blood pressure or arterial stiffness
  One small trial in older adults saw small improvements; results need replication.
• Weak Muscle and physical performance
  Several trials found no clear improvement in strength or exercise capacity in healthy adults.
• Weak Slowing ageing
  No evidence in humans that NR slows ageing or extends lifespan.

Evidence ratings are our plain-English summary of how much good human research exists, not a promise of results. How we rate evidence.

Dosage and timing

• Typical supplement dose is 250-300 mg once or twice daily.
• Trials have used up to around 1,000 mg daily for weeks to months; long-term safety at that level is less certain.
• It can be taken with or without food; take with food if you get nausea.
• No official recommended intake exists; check current guidance and the label.

Forms and what to look for

• NR chloride is the common form used in supplements and in most trials.
• Capsules are most convenient; powders are cheaper but harder to dose.
• Some brands combine NR with pterostilbene; the added benefit is not well proven.
• Check that the label states the NR amount, not a total "complex" weight.

What to expect, and when

• NAD+ levels in blood rise within days.
• Most people notice no obvious effect; studies of function run for weeks to months.
• Treat any perceived energy boost with caution, as placebo effects are strong.

Side effects

• Nausea or upset stomach.
• Flushing, though less common than with niacin.
• Headache, fatigue or dizziness in some people.
• Elevated liver enzymes have been reported in some cases; stop and seek advice if you notice symptoms such as jaundice.

Interactions

• No major well-established drug interactions.
• Other niacin forms: avoid stacking high doses of niacin, NMN and NR without advice.
• Chemotherapy: NAD+ supports cell metabolism, so check with your oncology team.
• Blood pressure medicines: may add slightly to the effect; monitor if relevant.

Who should avoid it

• Pregnant or breastfeeding women, due to lack of safety data.
• People with liver disease unless a clinician agrees.
• People with cancer or a history of it, until discussed with a clinician.
• Children and teenagers.

Risks and safety

• Long-term safety beyond a year or two has not been established.
• NR is a patented ingredient (Niagen) in many products; unbranded versions vary in quality.
• UK regulatory status has been reviewed in the past; check current Food Standards Agency position if relevant.
• Not on the WADA prohibited list as far as we know, but check current rules if you compete.

Buying well: quality and testing

• Choose brands using a recognised, tested NR ingredient and showing third-party test results.
• Check mg of NR chloride per capsule and the recommended daily serving.
• Be sceptical of claims about reversing ageing.
• Avoid marketplace sellers with no batch testing.

Bottom line

NR is one of the better-studied NAD+ boosters and reliably raises NAD+ in blood, but the evidence that this improves how you feel or how long you live is thin. It suits curious, informed adults who accept that it is an experiment. If you have liver, cancer or pregnancy-related concerns, speak to a clinician first.